The Traffic Analysis Zone (TAZ) layer is a geographic unit that represents a small area within the Metrolina region. It stores information related to the socioeconomic database and serves as the origin and destination for all tours. Each TAZ has a TAZ ID number that can be joined with the socioeconomic database.
The TAZ structure consists of 3,896 zones and spans 13 counties. Each TAZ is connected to the highway networks by centroid connectors. The TAZs were updated to reflect changes to the 2020 US Census block data.
External zones are defined using a polygon-based method. This means external stations are drawn as cordon TAZs just outside the study area, where traffic enters and leaves.